In recent years, in personal information equipment such as a mobile telephone, there has been an increasing need for disclosing information acquired by a sensor function included in the information equipment itself or data stored in the information equipment to registered friends, a family, and the like.
For example, there is a demand that a user B who is a family member of a user A desires to acquire position information obtained by a global positioning system (GPS) function included in a mobile telephone terminal P by equipment Q1 that the user B has in order to check the current location of the user A of the terminal P. Further, there is a demand that the user A desires to allow a friend C to view photographic data taken by a built-in camera of the terminal P and stored in the terminal P from equipment Q2 owned by the friend C.
One method to provide services that satisfy these needs includes a method of installing a server function in the mobile telephone terminal P, which is thus used to transmit the position information or photographic data stated above via server function processing upon receiving a request according to a certain protocol from an external device.
Such a method may include a method using generally-known Web technology, for example, which allows a Web server installed in a terminal to make a predetermined reply upon receiving a hyper text transfer protocol (HTTP) request, including a uniform resource locator (URL) and a port number, from an external device.
Generally speaking, the foregoing server function has been installed in a server device configured of a large-scale computer, for example, which performs authentication to confirm whether or not an authorized user is currently accessing using a client terminal, such as a mobile phone, via a network (e.g., Patent literature 1)
FIG. 6 is a sequence diagram of a case in which a mobile telephone terminal installing such a server function is remotely operated. FIG. 6 shows a flow of a case in which a user B uses a server function of a mobile telephone terminal P owned by another user A using his/her mobile telephone terminal Q.
First, the user B notifies the user A that the user B desires to use the server function of the terminal P. The notification is made from the user B to the user A using means such as telephone or e-mail. Upon receiving the notification, the user A starts up the server function included in the terminal P using input means of the terminal P such as key buttons or a touch panel.
Next, the user A notifies the user B of access control information and that the user B is able to perform remote operation using means such as telephone or e-mail. The access control information is information required to access the server function of the terminal P, and includes, for example, information such as URL, IP address, port number, and authentication password.
The user B tries to access the server function of the terminal P based on the access control information that is notified. After that, access authentication processing is performed by access permission information management means included in the terminal P.
More specifically, the user A registers in advance information regarding another terminal that is allowed to access the server function of the terminal P by access permission setting means included in the terminal P. For example, such information may be a telephone number or an individual identification number of another terminal, and these information are recorded in a management table included in the access permission information management means. The access permission information management means refers to the management table to determine whether the terminal which has requested the access is a terminal that has access permission.
When authentication is successfully completed, the terminal P notifies the terminal Q of the access permission. Then, the terminal Q is able to use the server function of the terminal P.
As another related technique, Patent literature 2 discloses a system that allows a mobile telephone to remotely operate a video recorder connected to the Internet using e-mail, to make a recording reservation.
As another related technique, Patent literature 3 discloses a technique of changing settings of a mobile telephone terminal such as ring volume or an e-mail address from another terminal by remote operation. Further, Patent literature 4 discloses a technique in which a control server that performs control of controlled terminals allocates a remote control right to a remote control terminal to permit an exclusive remote control to the controlled terminals, thereby achieving the exclusive remote control.